Aircraft parts may be subject to ice formation, in particular forward-facing surfaces. For example, ice may form on an inlet lip skin of an engine nacelle during flight. Ice that has formed on an aircraft part may alter aerodynamic properties of the aircraft and increase aircraft weight. This may lead to an increase in fuel consumption or require a different control of the aircraft, or both. Most severely, ice formation may lead to a loss of control over the aircraft. Moreover, a piece of ice that has formed may break off and damage an aircraft part. Such damage may then lead to one of the aforementioned consequences.
An aircraft is advantageously provided with an anti-icing system to prevent ice formation on one or more aircraft parts. In general, an anti-icing system heats an aircraft part that may be subject to ice formation, so as to prevent the latter. For that purpose, an anti-icing system may use hot compressed air that can be bled off from a turbine engine. A gas flow path conveys this hot compressed air toward the aircraft part that needs to be heated in order to prevent ice-formation.
An anti-icing system may comprise a so-called piccolo duct arranged along an inner surface of the aircraft part that requires anti-icing. The compressed hot air that has been bled off is applied to the piccolo duct. The piccolo duct comprises a plurality of relative small outlets that project the compressed hot air to the inner surface, which causes heating of the aircraft part that requires anti-icing. However, a piccolo duct adds weight to the aircraft, which causes an increase in fuel consumption.
Patent publication U.S. Pat. No. 4,688,745 describes an anti-icing system for an annular housing at a leading edge of a jet engine. Hot gases, such as air from a hot, high pressure section of the jet engine are directed through a conduit, which enters the annular housing through a bulkhead. The conduit then turns about 90° to a direction tangential to a leading edge annulus. The hot gases that exit the conduit entrain cooler air in the annular housing, causing a larger mass of air to swirl circularly around the annular housing.